The Stack Report: The Router That Would Have Told Us

A Warning Eight Months Late

Version 7.21 of the firmware on your home router added one line to its changelog that I want to read to you in full, because tonight you paid for not having it. Network: added IPv4 subnet conflict warning and notification. That shipped on 17 February. Your router was still on a January build when you plugged a bridge from your dad's flat into its WAN port, and both ends of the cable turned out to believe they were the same 192 168 1 network.

It is Saturday, 26 September. The firmware you replaced tonight was built on 21 January. That is eight months, 34 patched vulnerabilities, and one unplugged fibre modem ago.

Here is roughly what the new firmware would have said, in spirit if not in exact wording.

Your WAN network overlaps your LAN network. Traffic may not go where you think it goes.

[sigh] Honesty requires the next paragraph. That warning would have saved ten minutes, not the evening. The evening went to the box that brings fibre into your dad's flat, which had been unplugged during the install and was sitting there, perfectly healthy, connected to nothing. The Netgear at the far end handed out addresses, answered pings, and politely forwarded every packet toward a cable that went nowhere. No changelog in the world fixes that.

For the record, the conflict got solved the right way round. The house has something like 8 things hard coded to the 192 168 1 network, pinkserver among them, so instead of renumbering home, your dad's flat is now the 192 168 2 network. He will never notice. His router got a firmware update out of the deal as well, so arguably he came out ahead.

Your 5G Router Is Wired Now

The more interesting story is what this router is for now. You own an industrial 5G router, and as of this evening its internet arrives over a cable from a point to point bridge. The 5G modem has been demoted to fallback. At its current spot that fallback reads a signal power of minus 113 and a signal to noise ratio of minus 3, which is a signal best described as theoretical. So I read eight months of changelog through a new lens: what matters to a wired router whose SIM card still has 2 jobs, backup internet and the fleet's text messages.

First door. Version 7.22 added a single signal quality number, blended from the individual radio measurements, and 7.23 added an event for it, so the router itself can react when quality drops. For you this is not about 5G speed. That SIM carries every text message popcorn2 sends through Brevduvan. Today nothing measures the health of that path at the source. You find out it is weak when a message does not arrive. A signal quality event feeding your telemetry would turn a silent failure into a line on a dashboard. That is a session, not an afternoon.

Second door. Until version 7.24.5, the router's built in speed test could not connect to most servers, which is the kind of changelog line that tells you nobody was using it. It works now. Tonight's number, 41 down and 78 up, came from your Mac over the router's Wi-Fi, so it measured the Wi-Fi and the bridge at the same time. Run the test on the router and you measure the bridge alone. Upload beating download says the direction from your dad's end to yours is the weak one, and that is exactly what better aim fixes. When you re-aim, the router's speed test and the bridge's signal page are the two instruments you want open side by side.

Third door, smaller. Tailscale on the router got a memory limit in 7.22 and a RAM diet in 7.24.5. Right now remote access to your home network goes through pinkserver. Tonight pinkserver froze when the router moved and took that route down with it. The router is the one box in the house that has to be up for anything else to work, which makes it the natural home for that job. An afternoon, and only worth it if reaching the house matters on days when the Pi is having a bad one.

Things I read and threw away. Multipath TCP arrived in the kernel in 7.23, and it sounds like it would bond your cable and your 5G into one fat pipe. It will not. Both ends have to speak it, and the internet at large does not. The web interface got a dark theme, which is nice. It also got 2 factor login for the web interface and for SSH, and you should leave that off for SSH unless you enjoy reading codes aloud to Claude every time it wants to check a tunnel.

The Part That Paid For The Flash

Between your old build and the one you are running now, 34 separate vulnerabilities were patched, and 21 of them are rated high or critical. The critical one, 9.1 out of 10, landed in 7.22 in March. This router is the front door of your house network and the gateway for the fleet's text messages. That list alone justified tonight.

A few fixes touch your setup directly. Version 7.21 fixed WireGuard tunnels failing to start after a reboot, and you run 4 of them. Version 7.24 fixed the clock failing to sync when there is no mobile connection, which is precisely the life this router now lives. I should add that the clock still jumped once after tonight's reboot, and WireGuard grumbled that time had run backwards. The tunnels shrugged, re-keyed on schedule, and carried on. File it under cosmetic.

Three Things About To Bite

None of these are new tonight. The upgrade just made me look.

One. Automatic failover is not actually switched on. The router prefers the cable because it has a lower route cost, and that is the whole mechanism. If your dad's line dies while the bridge stays linked, the router keeps sending everything into the dead cable, the 5G sits there unused, and the text message tunnel goes down with the internet. Turning on failover with proper connection checks is a 5 minute change whenever you say the word.

Two. The router has 2 tunnels to your nameservers, and the one to es-ns2 has not completed a handshake in 41 days. That lane is the backup text message path for the day when popcorn2 and pinkserver are both dark, and half of it has been dark since the middle of August. It is a job for the operations session, not for tonight.

Three. You took Stable, 7.24.5, and skipped Latest, 7.25. Correct call for a box that carries the fleet's texts. But 7.25 is where the features for this particular house live. It reloads the modem when it has been unable to reach an operator for a long time, and it can trigger a reconnect or a SIM switch based on signal quality rather than raw signal strength. Version 7.25.2 also carries another high severity patch. When 7.25 is promoted to Stable, take it.

If I Were You

The single thing I would look at next is the aiming session, with the router's own speed test open next to the bridge's signal page. And the next time you are at your dad's flat, a strip of tape across that fibre box cable.